THE SECRET OF THE WILLOW WREN 137 



on account of their supernatural character have 

 very remarkable voices with a human sound in 

 them : the raven with his angry, barking cry, 

 and deep, solemn croak ; the booming bittern ; 

 and the white or church owl, with his sepulchral 

 screech. 



It is, I think, plain that the various sensations 

 excited in us by the cries, moans, and screams, 

 and the more or less musical notes of different 

 species, are due to the human emotions which 

 they express or seem to express. If the voice 

 simulates that of a maniac, or of a being tortured 

 in body or mind, or overcome with grief, or 

 maddened with terror, the blood-curdling and 

 other sensations proper to the occasion will be 

 experienced ; only, if we are familiar with the 

 sound or know its cause, the sensation will be 

 weak. Similarly, if in some deep, silent wood 

 we are suddenly startled by a loud human 

 whistle or shouted " Hi ! " although we may 

 know that a bird, somewhere in that waste of 

 foliage around us, uttered the shout, we yet 

 cannot help experiencing the feelings — a com- 

 bination of curiosity, amusement, and irritation 

 — which we should have if some friend or some 



